A variety of metal stock benders using manual power only are available which use a compound lever to increase the amount of power applied to bending the metal. Examples are J. Wood, U.S. Pat. No. 757,078; J. Garton, U.S. Pat. No. 2,424,024; H. M. James, U.S. Pat. No. 2,701,001 and B. Fjellstrom, U.S. Pat. No. 3,763,685.
None of these patents address the problem presented when a compound lever arrangement is used to increase the amount of power applied, namely the corresponding reduction in bending range as the leverage is increased, which is directly proportional to the increase in power obtained by the compound lever.
An additional problem not addressed is means for changing the bend radius and shape readily.